Heraeus Megafuge 1.0 "OPEN" message stays in display

OPEN" message stays in the display all the time, no matter lid is open or closed. I checked lid micro switches, motor over temp.switch and frequency drive over temp.switch. It is all right. I checked voltage on terminal XA when lid is open and it is 12.8V, not 33V DC as it should be by service manual.  Resistor R13 is burned and I can't see its value.  Could anybody tell me which value this resistor should be CCould anybody tell me which value this resistor should be ?"

Thank you